JP5900451B2 - Electrophotographic photoreceptor, image forming apparatus and image forming method - Google Patents

Description

  The present invention relates to an electrophotographic photosensitive member provided in an electrophotographic image forming apparatus, an image forming apparatus including the electrophotographic photosensitive member, and an image forming method using the electrophotographic photosensitive member.

  Conventionally, an inorganic photoreceptor and an organic photoreceptor are known as an electrophotographic photoreceptor (hereinafter also simply referred to as “photoreceptor”) used in an electrophotographic image forming apparatus. The “electrophotographic method” here generally means that a photoconductive photoreceptor is first charged in a dark place by, for example, corona discharge, and then exposed to selectively dissipate the charge only in the exposed portion, thereby electrostatically charging. This is an image forming process in which a latent image is obtained, and this latent image portion is developed with a toner composed of a colorant such as a dye and a pigment, and a resin material, and visualized to form an image.

  Compared to inorganic photoreceptors, organic photoreceptors have advantages in terms of freedom of photosensitive wavelength range, film formability, flexibility, film transparency, mass productivity, toxicity, cost, etc. An organic photoreceptor is used for the body.

In recent years, by providing a surface layer of a cross-linked curable resin on the surface of an organic photoreceptor, the wear resistance, scratch resistance, and environmental stability are improved, and the life can be extended.
Such a surface layer has a relatively smooth surface, a small surface roughness, and is less likely to be rough than a surface layer that is not a surface layer of a cross-linked curable resin. Therefore, there is a problem that the contact area with the cleaning blade is increased, the torque is increased, intense stick-slip vibration is caused, and cleaning failure is likely to occur. In order to solve this problem, as disclosed in, for example, Patent Document 1 and Patent Document 2, a lubricant is supplied to the surface of the photoconductor, and the adhesion between the photoconductor and the toner, the photoconductor and the cleaning blade, The adhesion force between is reduced.

  However, as in Patent Document 2, for example, in a method in which a lubricant is added to a developer and the lubricant is supplied to the surface of the photoreceptor by a developing bias in the development process, a sufficient amount of lubricant is supplied to the surface of the photoreceptor. In some cases, the adhesion force cannot be sufficiently reduced, and good cleaning properties cannot be obtained. Even when the charging method performed in the charging process is a roller charging method, the discharge product easily adheres to the surface of the photosensitive member, and the above-mentioned adhesion force cannot be sufficiently reduced, and the cleaning property is excellent. There is a problem that you can not get. On the other hand, increasing the supply amount of the lubricant improves the cleaning performance, but it tends to cause uneven supply of the lubricant due to the difference in the image printing rate. There is a problem that an image density difference occurs.

JP 2003-149995 A JP 2007-94240 A

  The present invention has been made in consideration of the circumstances as described above, and an object thereof is an electrophotographic photosensitive member having good cleaning properties and suppressing occurrence of density unevenness in the formed image, An object of the present invention is to provide an image forming apparatus and an image forming method.

In the electrophotographic photosensitive member of the present invention, a photosensitive layer is formed on a conductive support, and a surface layer is formed on the photosensitive layer.
The surface layer is formed by containing organic resin fine particles and metal oxide fine particles in a cured resin that is a polymerization reaction product of a compound having two or more radical polymerizable functional groups,
The organic resin fine particles are made of a resin containing a structural unit derived from at least one of melamine and benzoguanamine, and have a number average primary particle size of 0.01 to 3.00 μm.

  In the electrophotographic photosensitive member of the present invention, the organic resin fine particles are preferably composed of a polycondensate of melamine and formaldehyde.

  In the electrophotographic photosensitive member of the present invention, it is preferable that the organic resin fine particles are contained at a ratio of 5 to 40 parts by mass with respect to 100 parts by mass of the cured resin.

  In the electrophotographic photoreceptor of the present invention, it is preferable that the metal oxide fine particles are surface-treated with a surface treatment agent comprising a compound having a radical polymerizable functional group.

  In the electrophotographic photoreceptor of the present invention, the cured resin is preferably an acrylic resin.

  In the electrophotographic photosensitive member of the present invention, the surface layer preferably contains a charge transporting compound.

The image forming apparatus of the present invention includes an electrophotographic photosensitive member, a charging unit that charges the surface of the electrophotographic photosensitive member, an exposure unit that forms an electrostatic latent image on the surface of the electrophotographic photosensitive member, and the electrostatic unit. Developing means for developing a latent image with a developer containing toner to form a toner image, transfer means for transferring the toner image to a transfer material, and fixing means for fixing the toner image transferred to the transfer material; Cleaning means for removing residual toner on the electrophotographic photosensitive member,
Having a lubricant application mechanism for applying a lubricant to the surface of the electrophotographic photoreceptor,
The electrophotographic photosensitive member is the above-described electrophotographic photosensitive member.

  In the image forming apparatus of the present invention, it is preferable that the charging unit is of a contact or non-contact roller charging type.

The image forming method of the present invention includes a charging step for charging the surface of the electrophotographic photosensitive member, an exposure step for forming an electrostatic latent image on the surface of the electrophotographic photosensitive member, and the electrostatic latent image containing toner. A developing process for developing with a developer to form a toner image, a transferring process for transferring the toner image to a transfer material, a fixing process for fixing the toner image transferred to the transfer material, and an electrophotographic photoreceptor A cleaning process for removing residual toner,
The developer includes a lubricant;
The electrophotographic photosensitive member described above is used as the electrophotographic photosensitive member.

  In the image forming method of the present invention, the charging step is preferably performed by a contact or non-contact roller charging method.

  According to the electrophotographic photosensitive member of the present invention, the cured resin constituting the surface layer contains organic resin fine particles and metal oxide fine particles made of a resin containing a structural unit derived from at least one of melamine and benzoguanamine. In addition, since the organic resin fine particles have a particle size in a specific range, the organic resin fine particles have good cleaning properties, and the occurrence of density unevenness in the formed image is suppressed.

  According to the image forming apparatus of the present invention, it is possible to form a high-quality image over a long period of time by providing the electrophotographic photosensitive member, and it is possible to form an uneven supply of lubricant. Even when this occurs, the occurrence of uneven image density is suppressed.

  According to the image forming method of the present invention, by using the electrophotographic photosensitive member, a good cleaning property can be obtained, so that a high-quality image can be formed over a long period of time, and uneven supply of the lubricant. Even when this occurs, the occurrence of uneven image density is suppressed.

FIG. 3 is an explanatory cross-sectional view illustrating an example of a layer configuration in the photoreceptor of the present invention. It is sectional drawing for description which shows an example of a structure of the circular slide hopper coating device used for the manufacturing method of the photoreceptor of this invention. It is a perspective sectional view of the circular slide hopper coating device shown in FIG. 1 is a cross-sectional view illustrating the configuration of an example of an image forming apparatus according to the present invention. FIG. 3 is an explanatory cross-sectional view illustrating a configuration in an example of an image forming unit in the image forming apparatus of the present invention. The evaluation image used in evaluation of an Example is shown.

  Hereinafter, the present invention will be described in detail.

[Electrophotographic photoconductor]
The photoreceptor of the present invention is not particularly limited as long as the photosensitive layer and the surface layer are laminated in this order on the conductive support. Specifically, the following (1) and (2) layer configurations Is mentioned.
(1) A layer structure in which a charge generation layer, a charge transport layer, and a surface layer are laminated in this order as an intermediate layer and a photosensitive layer on a conductive support.
(2) A layer structure in which an intermediate layer, a single layer containing a charge generation material and a charge transport material as a photosensitive layer, and a surface layer are laminated in this order on a conductive support.

  FIG. 1 is an explanatory cross-sectional view showing an example of the layer structure of the photoreceptor of the present invention. Specifically, the layer configuration of (1) above is shown. In this photoreceptor, a photosensitive layer 102 is laminated on an electroconductive support 101 via an intermediate layer 103, and a surface layer 106 is laminated on the photosensitive layer 102. The photosensitive layer 102 includes a charge generation layer 104 stacked on the intermediate layer 103 and a charge transport layer 105 stacked on the charge generation layer 104. The surface layer 106 contains organic resin fine particles 107a and metal oxide fine particles 107b.

  The photoconductor of the present invention is an organic photoconductor, and an electrophotographic photoconductor in which at least one of a charge generation function and a charge transport function essential to the configuration of an electrophotographic photoconductor is expressed by an organic compound. And a photoreceptor composed of a known organic charge generation material or organic charge transport material, a photoreceptor composed of a polymer complex with a charge generation function and a charge transport function, and the like.

  The photoreceptor of the present invention is of a negative charge type. When this negatively charged photoreceptor is exposed after its surface is negatively charged, a charge is generated in the charge generation layer (photosensitive layer in the case of a single layer), of which negative charges (electrons) Moves through the intermediate layer to the conductive support, while holes move through the charge transport layer (photosensitive layer) to the surface of the organophotoreceptor, counteracting the negative charge on the surface and electrostatic latent image Is formed.

[Surface layer]
The surface layer constituting the photoconductor of the present invention contains a structural unit derived from at least one of melamine and benzoguanamine in a cured resin obtained by polymerizing a compound having two or more radically polymerizable functional groups. The organic resin fine particles having a number average primary particle size of 0.01 to 3.00 μm and metal oxide fine particles are contained.

(Cured resin)
The cured resin is a main component constituting the surface layer. This cured resin is obtained by polymerizing a compound having two or more radical polymerizable functional groups (hereinafter also referred to as “polyfunctional radical polymerizable compound”). Specifically, the curable resin is formed by polymerizing and curing a polyfunctional radical polymerizable compound by irradiation with active rays such as ultraviolet rays and electron beams.

As the monomer for forming the curable resin, a polyfunctional radical polymerizable compound is used, but a compound having one radical polymerizable functional group (hereinafter also referred to as “monofunctional radical polymerizable compound”) is used in combination. You can also. In the case of using a monofunctional radically polymerizable compound, the proportion is preferably 0 to 30% by mass with respect to the total amount of monomers for forming the cured resin.
Examples of the radical polymerizable functional group include a vinyl group, an acryloyl group, and a methacryloyl group.

Since the polyfunctional radical polymerizable compound can be cured in a small amount of light or in a short time, an acryloyl group (CH ₂ ═CHCO—) or a methacryloyl group (CH ₂ ═CCH ₃ CO—) is used as the radical polymerizable functional group. ) Is particularly preferably an acrylic monomer having two or more) or oligomers thereof. Accordingly, the curable resin is preferably an acrylic resin formed from an acrylic monomer or an oligomer thereof.

  In the present invention, the polyfunctional radically polymerizable compound may be used alone or in combination. In addition, these polyfunctional radical polymerizable compounds may use monomers, but may be used after oligomerization.

  Hereinafter, specific examples of the polyfunctional radically polymerizable compound are shown.

However, in the chemical formulas showing the exemplary compounds (M1) to (M14), R represents an acryloyl group (CH ₂ ═CHCO—) and R ′ represents a methacryloyl group (CH ₂ ═CCH ₃ CO—).

(Organic resin fine particles)
The organic resin fine particles are made of a resin containing a structural unit derived from at least one of melamine and benzoguanamine. Specific examples of such resins include melamine resins such as polycondensates of melamine and formaldehyde, copolycondensates of melamine, benzoguanamine, and formaldehyde; polycondensates of benzoguanamine and formaldehyde, and the like. Examples include benzoguanamine resin. The organic resin fine particles are preferably made of a polycondensate of melamine and formaldehyde from the viewpoint of toner cleaning properties and suppression of image density unevenness.

The number average primary particle diameter of the organic resin fine particles is 0.01 to 3.00 μm, preferably 0.1 to 2.0 μm.
When the number average primary particle size of the organic resin fine particles is within the above range, the surface of the photoreceptor can be appropriately roughened, and good cleaning properties can be ensured.

In the present invention, the number average primary particle size of the organic resin fine particles is measured as follows.
First, as a measurement sample, a photosensitive layer including a surface layer is cut out from the surface of the photoreceptor with a knife or the like, and attached to an arbitrary holder so that the cut surface faces upward.
And a measurement sample is computed from the photograph image observed and image | photographed with the scanning electron microscope. A photograph is taken with the magnification of the microscope set at 30,000 times, and 100 particles are randomly extracted from the photograph image and calculated. Specifically, a photographic image is binarized by an automatic image processing analyzer “LUZEX AP” (manufactured by Nireco), the horizontal ferret diameter of 100 fine particles is measured, and an average value is calculated. The number average primary particle size is used.

  In the present invention, when the organic resin fine particles are contained in the surface layer, an appropriate surface roughness can be imparted to the surface of the photoreceptor, and good cleaning properties can be ensured. The melamine resin and benzoguanamine resin are positively charged, and the charging sequence of the resin, the negatively charged toner, and the lubricant is “negatively charged toner”-“lubricant (for example, zinc stearate)”. -Since it becomes a “melamine resin and benzoguanamine resin”, even when uneven supply of the lubricant occurs, the surface of the photosensitive member containing the organic resin fine particles is more than the contact charge between the negatively chargeable toner and the lubricant. Contact charging with the negatively chargeable toner becomes dominant, it is possible to prevent occurrence of potential unevenness due to contact charging between the toner and the lubricant, and to suppress occurrence of density unevenness of the formed image.

The organic resin fine particles are preferably contained at a rate of 5 to 40 parts by mass, more preferably 10 to 30 parts by mass with respect to 100 parts by mass of the cured resin.
When the content ratio of the organic resin fine particles is within the above range, the organic resin fine particles are exposed on the surface of the photoreceptor in relation to the number average primary particle size, and this is a case where uneven supply of the lubricant occurs. However, contact charging between the surface of the photoreceptor containing the organic resin fine particles and the negatively chargeable toner becomes dominant, and the occurrence of unevenness in image density due to uneven supply of lubricant can be reliably suppressed.
When the content of the organic resin fine particles is excessive, there is a possibility that a desired latent image cannot be formed due to a decrease in light transmittance. On the other hand, when the content ratio of the organic resin fine particles is too small, the cleaning property is deteriorated due to the decrease in the surface roughness, and when uneven adhesion of the lubricant occurs on the surface of the photoreceptor, image density unevenness may be caused. There is.

  The organic resin fine particles as described above include melamine resin (polycondensate of melamine and formaldehyde) “Eposter S”, “Eposter S6”, benzoguanamine resin (polycondensate of benzoguanamine and formaldehyde) “Eposter MS” (above Commercial products such as Nippon Shokubai Co., Ltd.).

(Metal oxide fine particles)
The metal oxide fine particles are not particularly limited. For example, silica (silicon oxide), magnesium oxide, zinc oxide, lead oxide, alumina (aluminum oxide), zirconium oxide, tin oxide, titania (titanium oxide), niobium oxide, Molybdenum oxide, vanadium oxide, and the like can be used, and among these, tin oxide is preferable from the viewpoints of hardness, conductivity, and light transmittance.

  The number average primary particle size of the metal oxide fine particles is preferably 1 to 300 nm, more preferably 3 to 100 nm, and still more preferably 5 to 40 nm.

In the present invention, the number average primary particle size of the metal oxide fine particles is measured as follows.
First, as a measurement sample, a photosensitive layer including a surface layer is cut out from the surface of the photoreceptor with a knife or the like, and attached to an arbitrary holder so that the cut surface faces upward. The measurement sample is taken with a scanning electron microscope (manufactured by JEOL Ltd.) at a magnification of 10,000 times. Number of photographic images (excluding agglomerated particles) obtained by randomly capturing 300 particles with a scanner using an automatic image processing analyzer “LUZEX AP (software version Ver. 1.32)” (manufactured by Nireco) The average primary particle size was calculated.

The metal oxide fine particles are preferably those obtained by surface treatment with a surface treatment agent comprising a compound having a radical polymerizable functional group.
Specifically, the metal oxide fine particles are surface-treated with a surface treatment agent comprising a compound having a radical polymerizable functional group, so that the radical polymerizable functional group is introduced on the surface of the metal oxide fine particles. Is preferred.
When the metal oxide fine particles are surface-treated with a surface treatment agent comprising a compound having a radical polymerizable functional group, the radical polymerizable compound is formed in the surface layer forming step in the photoreceptor production process described later. Can form a cross-linked structure, and the film strength of the surface layer can be sufficiently obtained. Moreover, high dispersibility is obtained for the metal oxide fine particles in the cured resin.

  Examples of the radical polymerizable functional group in the surface treatment agent include a vinyl group, an acryloyl group, and a methacryloyl group. Such a radical polymerizable functional group can react with a radical polymerizable compound that forms a cured resin to form a surface layer having high film strength. As the surface treatment agent having a radical polymerizable functional group, a silane coupling agent having a polymerizable functional group such as a vinyl group, an acryloyl group, or a methacryloyl group is preferable.

  Hereinafter, specific examples of the surface treatment agent comprising a compound having a radical polymerizable functional group will be shown.

_{S-1: CH 2 = CHSi} (CH 3) (OCH 3) 2
_{S-2: CH 2 = CHSi} (OCH 3) 3
S-3: CH ₂ = CHSiCl _{3
S-4: CH 2 = CHCOO} (CH 2) 2 Si (CH 3) (OCH 3) 2
_{S-5: CH 2 = CHCOO} (CH 2) 2 Si (OCH 3) 3
_{S-6: CH 2 = CHCOO} (CH 2) 2 Si (OC 2 H 5) (OCH 3) 2
_{S-7: CH 2 = CHCOO} (CH 2) 3 Si (OCH 3) 3
_{S-8: CH 2 = CHCOO} (CH 2) 2 Si (CH 3) Cl 2
_{S-9: CH 2 = CHCOO} (CH 2) 2 SiCl 3
_{S-10: CH 2 = CHCOO} (CH 2) 3 Si (CH 3) Cl 2
S-11: CH ₂ = CHCOO (CH ₂ ) ₃ SiCl _{3
S-12: CH 2 = C} (CH 3) COO (CH 2) 2 Si (CH 3) (OCH 3) 2
_{S-13: CH 2 = C} (CH 3) COO (CH 2) 2 Si (OCH 3) 3
_{S-14: CH 2 = C} (CH 3) COO (CH 2) 3 Si (CH 3) (OCH 3) 2
_{S-15: CH 2 = C} (CH 3) COO (CH 2) 3 Si (OCH 3) 3
_{S-16: CH 2 = C} (CH 3) COO (CH 2) 2 Si (CH 3) Cl 2
_{S-17: CH 2 = C} (CH 3) COO (CH 2) 2 SiCl 3
_{S-18: CH 2 = C} (CH 3) COO (CH 2) 3 Si (CH 3) Cl 2
_{S-19: CH 2 = C} (CH 3) COO (CH 2) 3 SiCl 3
_{S-20: CH 2 = CHSi} (C 2 H 5) (OCH 3) 2
_{S-21: CH 2 = C} (CH 3) Si (OCH 3) 3
_{S-22: CH 2 = C} (CH 3) Si (OC 2 H 5) 3
_{S-23: CH 2 = CHSi} (OCH 3) 3
_{S-24: CH 2 = C} (CH 3) Si (CH 3) (OCH 3) 2
_{S-25: CH 2 = CHSi} (CH 3) Cl 2
_{S-26: CH 2 = CHCOOSi} (OCH 3) 3
_{S-27: CH 2 = CHCOOSi} (OC 2 H 5) 3
_{S-28: CH 2 = C} (CH 3) COOSi (OCH 3) 3
_{S-29: CH 2 = C} (CH 3) COOSi (OC 2 H 5) 3
_{S-30: CH 2 = C} (CH 3) COO (CH 2) 3 Si (OC 2 H 5) 3
_{S-31: CH 2 = CHCOO} (CH 2) 2 Si (CH 3) 2 (OCH 3)
_{S-32: CH 2 = CHCOO} (CH 2) 2 Si (CH 3) (OCOCH 3) 2
_{S-33: CH 2 = CHCOO} (CH 2) 2 Si (CH 3) (ONHCH 3) 2
_{S-34: CH 2 = CHCOO} (CH 2) 2 Si (CH 3) (OC 6 H 5) 2
_{S-35: CH 2 = CHCOO} (CH 2) 2 Si (C 10 H 21) (OCH 3) 2
_{S-36: CH 2 = CHCOO} (CH 2) 2 Si (CH 2 C 6 H 5) (OCH 3) 2

  Moreover, as a surface treating agent, you may use the silane compound which has a reactive organic group in which radical polymerization is possible other than what is shown to the said exemplary compound (S-1)-(S-36).

  The surface treatment agents may be used alone or in combination of two or more.

  It is preferable that the processing amount of a surface treating agent is 0.1-200 mass parts with respect to 100 mass parts of untreated metal oxide fine particles, More preferably, it is 7-70 mass parts.

  Examples of the treatment method for the untreated metal oxide fine particles of the surface treatment agent include a method of wet crushing a slurry (suspension of solid particles) containing the untreated metal oxide fine particles and the surface treatment agent. It is done. By this method, re-aggregation of the metal oxide fine particles is prevented and at the same time the surface treatment of the metal oxide fine particles proceeds. Thereafter, the solvent is removed to form powder.

  Examples of the surface treatment apparatus include a wet media dispersion type apparatus. In this wet media dispersion type apparatus, beads are filled as media in a container, and a stirring disk mounted perpendicularly to the rotation axis is rotated at high speed to crush and pulverize and disperse the aggregated particles of metal oxide fine particles. It is an apparatus having a process, and the configuration thereof is not limited as long as the metal oxide fine particles are sufficiently dispersed and can be surface-treated when the surface treatment is performed on the metal oxide fine particles. Various types such as horizontal type, continuous type and batch type can be adopted. Specifically, a sand mill, ultra visco mill, pearl mill, glen mill, dyno mill, agitator mill, dynamic mill and the like can be used. These dispersion-type devices are finely pulverized and dispersed by impact crushing, friction, shearing, shear stress, etc., using a grinding medium (media) such as balls and beads.

  As beads used in the wet media dispersion type apparatus, balls made of glass, alumina, zircon, zirconia, steel, flint stone, etc. can be used, but those made of zirconia or zircon are particularly preferable. Further, as the size of the beads, those having a diameter of about 1 to 2 mm are usually used, but in the present invention, those having a diameter of about 0.1 to 1.0 mm are preferably used.

  Various materials such as stainless steel, nylon and ceramic can be used for the disk and container inner wall used in the wet media dispersion type apparatus. In the present invention, the disk and container inner wall made of ceramic such as zirconia or silicon carbide are particularly used. Is preferred.

It is preferable that metal oxide microparticles | fine-particles are contained in the ratio of 60-100 mass parts with respect to 100 mass parts of cured resin, More preferably, it is 70-90 mass parts.
When the content ratio of the metal oxide fine particles is within the above range, it is possible to sufficiently satisfy hardness, conductivity, and light transmittance.
In the case where the content of the metal oxide fine particles is excessive, there is a possibility that the latent image formation may be affected due to a decrease in light transmittance, or image defects accompanying aggregation. On the other hand, when the content ratio of the metal oxide fine particles is too small, there is a risk of deterioration in wear resistance accompanying a decrease in hardness and density unevenness during high-speed printing due to a decrease in sensitivity.

(Charge transporting compound)
The surface layer preferably contains a charge transporting compound.
The charge transporting compound is not particularly limited as long as it has a charge transporting property for transporting charge carriers in the surface layer, but is particularly preferably a compound represented by the following general formula (1).
In the photoreceptor of the present invention, the charge transport compound is contained in the surface layer, so that sufficient responsiveness can be ensured even during high-speed printing.
The charge transporting compound used in the present invention is not reactive with a surface treatment agent comprising a polyfunctional radical polymerizable compound or a compound having a radical polymerizable functional group.

In general formula (1), R ¹ and R ² each independently represents a hydrogen atom or a methyl group. R ³ is a linear or branched alkyl group having 1 to 5 carbon atoms, preferably a propyl group, a pentyl group, or a butyl group.

  Specific examples of the compound represented by the general formula (1) are shown below.

  The compound represented by the general formula (1) can be synthesized by a known synthesis method, for example, a method disclosed in JP-A-2006-143720.

The charge transporting compound is preferably contained in a proportion of 10 to 30 parts by mass, more preferably 15 to 25 parts by mass with respect to 100 parts by mass of the cured resin.
When the content ratio of the charge transporting compound is within the above range, sufficient responsiveness is ensured even during high-speed printing.
When the content ratio of the charge transporting compound is excessive, the film strength of the surface layer is lowered, and the life of the photoreceptor may be shortened. On the other hand, when the content ratio of the charge transporting compound is too small, the amount of hole traps generated in the surface layer increases, and electrostatic image density unevenness is likely to occur.

  The surface layer according to the present invention may contain other components in addition to the cured resin, the organic resin fine particles, the metal oxide fine particles, and the charge transporting compound. For example, various antioxidants, for example, fluorine atoms Various lubricant particles such as resin particles can be added. Examples of the fluorine atom-containing resin particles include tetrafluoroethylene resin, trifluorinated ethylene chloride resin, hexafluoroethylene chloride propylene resin, vinyl fluoride resin, vinylidene fluoride resin, ethylene difluoride dichloride resin, and these One or two or more types are preferably selected from the copolymers, but tetrafluoroethylene resin and vinylidene fluoride resin are particularly preferable.

  The layer thickness of the surface layer is preferably 0.2 to 10 μm, more preferably 0.5 to 6 μm.

  Hereinafter, the configuration of the photoconductor other than the surface layer will be described in the case of the layer configuration (1).

[Conductive support]
The conductive support constituting the photoreceptor of the present invention may be any conductive support, for example, a metal such as aluminum, copper, chromium, nickel, zinc and stainless steel formed into a drum or sheet, A metal foil such as aluminum or copper laminated on a plastic film, a metal film deposited with aluminum, indium oxide, tin oxide or the like, a metal provided with a conductive layer by applying a conductive material alone or with a binder resin, Examples include plastic film and paper.

[Middle layer]
In the photoreceptor of the present invention, an intermediate layer having a barrier function and an adhesive function can be provided between the conductive support and the photosensitive layer. In consideration of various failure prevention, it is preferable to provide an intermediate layer.

  Such an intermediate layer contains, for example, a binder resin (hereinafter also referred to as “binder resin for intermediate layer”) and, if necessary, conductive particles and metal oxide particles.

  Examples of the intermediate layer binder resin include casein, polyvinyl alcohol, nitrocellulose, ethylene-acrylic acid copolymer, polyamide resin, polyurethane resin, and gelatin. Among these, alcohol-soluble polyamide resins are preferable.

The intermediate layer can contain various conductive particles and metal oxide particles for the purpose of adjusting the resistance. For example, various metal oxide particles such as alumina, zinc oxide, titanium oxide, tin oxide, antimony oxide, indium oxide, and bismuth oxide can be used. Ultrafine particles such as indium oxide doped with tin, tin oxide doped with antimony, and zirconium oxide can be used.
The number primary average particle diameter of such metal oxide particles is preferably 0.3 μm or less, more preferably 0.1 μm or less.

  These metal oxide particles may be used alone or in combination of two or more. When two or more kinds are mixed, it may take the form of a solid solution or fusion.

  The content ratio of the conductive particles or the metal oxide particles is preferably 20 to 400 parts by mass, more preferably 50 to 350 parts by mass with respect to 100 parts by mass of the binder resin.

  The thickness of the intermediate layer is preferably 0.1 to 15 μm, more preferably 0.3 to 10 μm.

(Charge generation layer)
The charge generation layer in the photosensitive layer constituting the photoreceptor of the present invention contains a charge generation material and a binder resin (hereinafter also referred to as “binder resin for charge generation layer”).

  Examples of charge generation materials include azo raw materials such as Sudan Red and Diane Blue, quinone pigments such as pyrenequinone and anthanthrone, quinocyanine pigments, perylene pigments, indigo pigments such as indigo and thioindigo, pyranthrone and diphthaloylpyrene. Examples thereof include, but are not limited to, ring quinone pigments and phthalocyanine pigments. Among these, polycyclic quinone pigments and titanyl phthalocyanine pigments are preferable. These charge generation materials may be used alone or in combination of two or more.

  As the binder resin for the charge generation layer, known resins can be used. For example, polystyrene resin, polyethylene resin, polypropylene resin, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, epoxy resin, Polyurethane resins, phenol resins, polyester resins, alkyd resins, polycarbonate resins, silicone resins, melamine resins, and copolymer resins containing two or more of these resins (eg, vinyl chloride-vinyl acetate copolymer resins, chlorides) Vinyl-vinyl acetate-maleic anhydride copolymer resin), poly-vinylcarbazole resin, and the like, but are not limited thereto. Among these, polyvinyl butyral resin is preferable.

  The content ratio of the charge generation material in the charge generation layer is preferably 1 to 600 parts by mass, more preferably 50 to 500 parts by mass with respect to 100 parts by mass of the binder resin for charge generation layer.

  The layer thickness of the charge generation layer varies depending on the characteristics of the charge generation material, the characteristics of the binder resin for the charge generation layer, the content ratio, etc., but is preferably 0.01 to 5 μm, more preferably 0.05 to 3 μm. is there.

(Charge transport layer)
The charge transport layer in the photosensitive layer constituting the photoreceptor of the present invention contains a charge transport material and a binder resin (hereinafter also referred to as “binder resin for charge transport layer”).

  Examples of the charge transport material for the charge transport layer include a charge transport material such as a triphenylamine derivative, a hydrazone compound, a styryl compound, a benzidine compound, and a butadiene compound.

  A known resin can be used as the binder resin for the charge transport layer. Polycarbonate resin, polyacrylate resin, polyester resin, polystyrene resin, styrene-acrylonitrile copolymer resin, polymethacrylic ester resin, styrene-methacrylic ester Examples of the resin include a copolymer resin, and a polycarbonate resin is preferable. Furthermore, BPA (bisphenol A) type, BPZ (bisphenol Z) type, dimethyl BPA type, BPA-dimethyl BPA copolymer type polycarbonate resin and the like are preferable in terms of crack resistance, wear resistance, and charging characteristics.

  The content ratio of the charge transport material in the charge transport layer is preferably 10 to 500 parts by weight, more preferably 20 to 250 parts by weight with respect to 100 parts by weight of the charge transport layer binder resin.

  The layer thickness of the charge transport layer varies depending on the characteristics of the charge transport material, the characteristics and the content ratio of the binder resin for the charge transport layer, and is preferably 5 to 40 μm, more preferably 10 to 30 μm.

  In the charge transport layer, an antioxidant, an electronic conductive agent, a stabilizer, silicone oil, or the like may be added. As the antioxidant, those disclosed in JP-A No. 2000-305291 and as the electronic conductive agent are disclosed in JP-A Nos. 50-137543 and 58-76483.

  According to the above photoreceptor, the cured resin constituting the surface layer contains organic resin fine particles and metal oxide fine particles composed of at least one of melamine resin and benzoguanamine resin. By having a particle size in a specific range, it has good cleaning properties and suppresses the occurrence of density unevenness in the formed image.

[Method for producing photoreceptor]
As a manufacturing method of the photoreceptor of the present invention, for example, it can be manufactured through the following steps.
Process (1): The process of forming an intermediate | middle layer by apply | coating the coating liquid for intermediate | middle layer formation to the outer peripheral surface of an electroconductive support body, and drying.
Step (2): A step of forming a charge generation layer by applying a coating solution for forming a charge generation layer on the outer peripheral surface of an intermediate layer formed on a conductive support and drying it.
Step (3): A step of forming a charge transport layer by applying a coating liquid for forming a charge transport layer to the outer peripheral surface of the charge generation layer formed on the intermediate layer and drying.
Step (4): The surface layer is formed by applying a coating solution for forming a surface layer on the outer peripheral surface of the charge transport layer formed on the charge generation layer to form a coating film, and curing the coating film. Forming.

[Step (1): Formation of intermediate layer]
The intermediate layer is prepared by dissolving the binder resin for the intermediate layer in a solvent to prepare a coating liquid (hereinafter also referred to as “intermediate layer forming coating liquid”), and if necessary, conductive particles and metal oxide particles. After the dispersion, the coating solution can be formed on the conductive support in a certain film thickness to form a coating film, and the coating film can be dried.

As a means for dispersing the conductive particles and metal oxide particles in the coating solution for forming the intermediate layer, an ultrasonic disperser, a ball mill, a sand mill, a homomixer, or the like can be used, but it is not limited to these. Absent.
Examples of the coating method for the intermediate layer forming coating solution include known dip coating methods, spray coating methods, spinner coating methods, bead coating methods, blade coating methods, beam coating methods, slide hopper methods, circular slide hopper methods, and the like. A method is mentioned.
The method for drying the coating film can be appropriately selected according to the type of solvent and the film thickness, but thermal drying is preferred.

  The solvent used in the intermediate layer forming step is not particularly limited as long as the conductive particles and the metal oxide particles are well dispersed and the binder resin for the intermediate layer is dissolved. Specifically, alcohols having 1 to 4 carbon atoms such as methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butanol, t-butanol, sec-butanol are excellent in binder resin solubility and coating performance. preferable. In addition, examples of co-solvents that can be used in combination with the above-described solvent to improve storage stability and particle dispersibility and obtain a preferable effect include benzyl alcohol, toluene, methylene chloride, cyclohexanone, and tetrahydrofuran.

  The concentration of the binder resin for the intermediate layer in the coating liquid for forming the intermediate layer is appropriately selected according to the thickness of the intermediate layer and the production rate.

[Step (2): Formation of Charge Generation Layer]
The charge generation layer is prepared by dispersing a charge generation material in a solution in which a charge generation layer binder resin is dissolved in a solvent to prepare a coating solution (hereinafter also referred to as “charge generation layer forming coating solution”). The coating solution can be formed on the intermediate layer by coating the intermediate layer with a certain film thickness to form a coating film and then drying the coating film.

As a means for dispersing the charge generation material in the charge generation layer forming coating solution, for example, an ultrasonic disperser, a ball mill, a sand mill, a homomixer or the like can be used, but is not limited thereto.
As a coating method for the charge generation layer forming coating solution, for example, dip coating method, spray coating method, spinner coating method, bead coating method, blade coating method, beam coating method, slide hopper method, circular slide hopper method and the like are known. The method is mentioned.
The method for drying the coating film can be appropriately selected according to the type of solvent and the film thickness, but thermal drying is preferred.

  Examples of the solvent used for forming the charge generation layer include toluene, xylene, methylene chloride, 1,2-dichloroethane, methyl ethyl ketone, cyclohexane, ethyl acetate, t-butyl acetate, methanol, ethanol, propanol, butanol, methyl cellosolve, Examples include, but are not limited to, 4-methoxy-4-methyl-2-pentanone, ethyl cellosolve, tetrahydrofuran, 1-dioxane, 1,3-dioxolane, pyridine, and diethylamine.

[Step (3): Formation of Charge Transport Layer]
The charge transport layer is prepared by preparing a coating liquid in which a binder resin for a charge transport layer and a charge transport material are dissolved in a solvent (hereinafter, also referred to as “coating liquid for forming a charge transport layer”). It can form by apply | coating to a fixed film thickness on a layer, forming a coating film, and drying the said coating film.

As a coating method of the coating solution for forming the charge transport layer, for example, dip coating method, spray coating method, spinner coating method, bead coating method, blade coating method, beam coating method, slide hopper method, circular slide hopper method and the like are known. The method is mentioned.
The method for drying the coating film can be appropriately selected according to the type of solvent and the film thickness, but thermal drying is preferred.

  Examples of the solvent used for forming the charge transport layer include toluene, xylene, methylene chloride, 1,2-dichloroethane, methyl ethyl ketone, cyclohexanone, ethyl acetate, butyl acetate, methanol, ethanol, propanol, butanol, tetrahydrofuran, and 1,4. -Dioxane, 1,3-dioxolane, pyridine, diethylamine and the like are exemplified, but not limited thereto.

[Step (4): Formation of surface layer]
The surface layer is formed by adding a polyfunctional radical polymerizable compound, organic resin fine particles, metal oxide fine particles, a polymerization initiator, and other components as required to a known solvent to a coating solution (hereinafter referred to as “surface layer forming coating”). The surface layer forming coating solution is applied to the outer peripheral surface of the charge transport layer formed in the step (3) to form a coating, and the coating is dried. A surface layer can be formed by polymerizing a radically polymerizable compound component in the coating film by irradiating an active ray such as an electron beam.

  The surface layer is formed by surface treatment with a surface treatment agent comprising a compound having a radical polymerizable functional group or a reaction between polyfunctional radical polymerizable compounds in the process of coating, drying and curing. In some cases, a crosslinkable curable resin is formed by a reaction between the radical polymerizable functional group of the surface treatment agent and the radical polymerizable functional group of the polyfunctional radical polymerizable compound.

  In the coating solution for forming the surface layer, the organic resin fine particles are 5 to 40 parts by mass with respect to 100 parts by mass of all monomers (polyfunctional radical polymerizable compound or monofunctional radical polymerizable compound) for forming the cured resin. It is preferable to contain by a ratio, More preferably, it is 10-30 mass parts. Further, the metal oxide fine particles should be contained in a proportion of 60 to 100 parts by mass with respect to 100 parts by mass of all monomers (polyfunctional radical polymerizable compound or monofunctional radical polymerizable compound) for forming the cured resin. Is more preferable, and it is 70-90 mass parts.

  As a means for dispersing the organic resin fine particles and metal oxide fine particles in the surface layer forming coating solution, an ultrasonic disperser, a ball mill, a sand mill, a homomixer, or the like can be used, but is not limited thereto. Absent.

  Any solvent can be used as the solvent for forming the surface layer as long as it can dissolve or disperse the polyfunctional radical polymerizable compound, organic resin fine particles and metal oxide fine particles. For example, methanol, ethanol, n-propyl Alcohol, isopropyl alcohol, n-butanol, t-butanol, sec-butanol, benzyl alcohol, toluene, xylene, methylene chloride, methyl ethyl ketone, cyclohexane, ethyl acetate, butyl acetate, methyl cellosolve, ethyl cellosolve, tetrahydrofuran, 1-dioxane, 1 , 3-dioxolane, pyridine, diethylamine, and the like, but are not limited thereto.

  As a coating method of the surface layer forming coating solution, for example, known methods such as dip coating method, spray coating method, spinner coating method, bead coating method, blade coating method, beam coating method, slide hopper method, circular slide hopper method, etc. A method is mentioned.

The coating solution for forming the surface layer is preferably applied using a circular slide hopper coating device.
Hereinafter, a method for applying the surface layer forming coating solution using the circular slide hopper coating apparatus will be described in detail.

  As shown in FIGS. 2 and 3, the circular slide hopper coating apparatus includes a cylindrical base 251, an annular coating head 260 provided so as to surround the periphery thereof, and a storage tank 254 for storing the coating liquid L. It consists of.

  The base material 251 here is a base material to which the surface layer forming coating solution is to be applied, for example, a state in which an intermediate layer and a photosensitive layer are formed on a conductive support (a surface layer is formed). Not).

The coating head 260 has a narrow coating liquid distribution slit 262 having a coating liquid outlet 261 that opens to the base 251 side along the entire direction of the annular coating head 260 along the direction perpendicular to the longitudinal direction of the base 251. Is formed over. The coating liquid distribution slit 262 communicates with the annular coating liquid distribution chamber 263, and the coating liquid distribution chamber 263 is supplied with the coating liquid L in the storage tank 254 through the supply pipe 264 by the pumping pump 255. Is formed.
On the lower side of the coating liquid outlet 261 of the coating liquid distribution slit 262, there is formed a slide surface 265 that is continuously inclined downward and is formed with a dimension slightly larger than the outer dimension of the substrate 251. Furthermore, a lip portion (bead; liquid reservoir portion) 266 extending downward from the end of the slide surface 265 is formed.

  In such a circular slide hopper coating apparatus, when the coating liquid L is pushed out from the coating liquid distribution slit 262 and allowed to flow down along the slide surface 265 in the process of moving the base 251 in the direction of the arrow, the slide surface 265 ends. The resulting coating liquid L forms a bead between the end of the slide surface 265 and the outer peripheral surface of the substrate 251, and is then applied to the surface of the substrate 251 to form a coating film F. Is discharged from the discharge port 267.

  In such a coating method using a circular slide hopper coating apparatus, the slide surface end and the base material are arranged with a certain gap (about 2 μm to 2 mm), so that the base material is not damaged and the layers have different properties. Even in the case of forming a multilayer, it can be applied without damaging the already applied layer. Furthermore, when multiple layers with different properties and dissolved in the same solvent are formed, the time in the solvent is much shorter compared to the dip coating method, so that the lower layer component hardly elutes to the upper layer side, so Can also be applied without degrading the dispersibility of metal oxide fine particles or organic resin fine particles, for example.

  The coating film may be cured without being dried, but it is preferable to perform the curing treatment after natural drying or heat drying.

  Drying conditions can be appropriately selected depending on the type of solvent, film thickness, and the like. The drying temperature is preferably room temperature to 180 ° C, particularly preferably 80 to 140 ° C. The drying time is preferably 1 minute to 200 minutes, and particularly preferably 5 minutes to 100 minutes.

  Examples of the method of polymerizing the radical polymerizable compound include a method of reacting by electron beam cleavage, a method of adding a radical polymerization initiator and reacting with light and heat. As the radical polymerization initiator, either a photopolymerization initiator or a thermal polymerization initiator can be used. A photopolymerization initiator and a thermal polymerization initiator can also be used in combination.

  As the radical polymerization initiator, a photopolymerization initiator is preferable, and among them, an alkylphenone compound or a phosphine oxide compound is preferable. In particular, a compound having an α-hydroxyacetophenone structure or an acylphosphine oxide structure is preferable.

  Hereinafter, specific examples of acylphosphine oxide compounds as photopolymerization initiators are shown.

  The polymerization initiators may be used alone or in combination of two or more.

  It is preferable that the addition ratio of a polymerization initiator is 0.1-20 mass parts with respect to 100 mass parts of radically polymerizable compounds, More preferably, it is 0.5-10 mass parts.

  As the curing treatment, the coating film is irradiated with actinic radiation, polymerized by generating radicals, and cured by forming a cross-linking bond by a cross-linking reaction between molecules and within the molecule, thereby producing a cured resin. As the actinic radiation, ultraviolet rays and electron beams are more preferred, and ultraviolet rays are particularly preferred because they are easy to use.

As the ultraviolet light source, any light source that generates ultraviolet light can be used without limitation. For example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, a flash (pulse) xenon, or the like can be used.
Irradiation conditions vary depending on each lamp, but the irradiation amount of active rays is usually 5 to 500 mJ / cm ² , preferably 5 to 100 mJ / cm ² .
The power of the lamp is preferably 0.1 kW to 5 kW, particularly preferably 0.5 kW to 3 kW.

  As an electron beam source, there is no particular limitation on the electron beam irradiation apparatus, and generally, an electron beam accelerator for electron beam irradiation is a curtain beam type that is relatively inexpensive and can provide a large output. Used. The acceleration voltage during electron beam irradiation is preferably 100 to 300 kV. The absorbed dose is preferably 0.5 to 10 Mrad.

  The irradiation time for obtaining the necessary amount of active ray irradiation is preferably 0.1 second to 10 minutes, and more preferably 0.1 second to 5 minutes from the viewpoint of work efficiency.

  In the step of forming the surface layer, drying can be performed before and after irradiation with active rays and during irradiation with active rays, and the timing of drying can be appropriately selected by combining these.

〔toner〕
The toner used in the image forming apparatus including the photoconductor of the present invention and the image forming method using the photoconductor of the present invention is not particularly limited, but a toner having a true sphere of 100 and a shape factor SF of less than 140 is preferable. . If the shape factor SF is less than 140, good transferability and the like are obtained, and the image quality of the obtained image is improved. The toner particles constituting the toner preferably have a volume average particle diameter of 2 to 8 μm from the viewpoint of achieving high image quality.

  The toner particles usually contain a binder resin and a colorant, and optionally contain a release agent. Any of the binder resin, the colorant, and the release agent may be any material that has been used in conventional toners, and is not particularly limited.

  The method for producing the toner particles is not particularly limited, and examples thereof include a normal pulverization method, a wet melt spheronization method prepared in a dispersion medium, suspension polymerization, dispersion polymerization, and emulsion polymerization aggregation method. Examples include known polymerization methods.

  Further, as the external additive, inorganic fine particles such as silica and titania having an average particle diameter of about 10 to 300 nm and an abrasive of about 0.2 to 3 μm can be externally added to the toner particles as appropriate. Further, the toner particles and a carrier composed of ferrite beads having an average particle diameter of 25 to 45 μm can be mixed and used as a two-component developer.

[Image forming apparatus]
The image forming apparatus of the present invention includes a photosensitive member, a charging unit for charging the surface of the photosensitive member, an exposure unit for forming an electrostatic latent image on the surface of the photosensitive member, and developing the electrostatic latent image with toner. A developing unit that forms a toner image; a transfer unit that transfers the toner image to a transfer material; a fixing unit that fixes the toner image transferred to the transfer material; and a cleaning unit that removes residual toner on the photoreceptor. The photosensitive member has a lubricant applying mechanism for applying a lubricant to the surface of the photosensitive member, and is provided with the photosensitive member of the present invention as the photosensitive member. The lubricant application mechanism includes, for example, grounding a solid lubricant, a brush that scrapes and supplies the solid lubricant, a driving source that drives the brush, and a casing that holds them to the ground before the cleaning blade. However, it is not limited.
The charging means is preferably of a contact or non-contact roller charging type.

FIG. 4 is a cross-sectional view illustrating the configuration of an example of the image forming apparatus of the present invention.
This image forming apparatus is called a tandem color image forming apparatus, and includes four sets of image forming units (image forming units) 10Y, 10M, 10C, and 10Bk, an endless belt-shaped intermediate transfer body unit 7, and paper feeding Means 21 and fixing means 24. A document image reading device SC is disposed on the upper part of the main body A of the image forming apparatus.

  The image forming unit 10Y for forming a yellow image includes a charging unit 2Y, an exposure unit 3Y, a developing unit 4Y, a primary transfer roller 5Y as a primary transfer unit, and a cleaning unit 6Y arranged around the drum-shaped photoreceptor 1Y. Have The image forming unit 10M that forms a magenta image includes a drum-shaped photoreceptor 1M, a charging unit 2M, an exposure unit 3M, a developing unit 4M, a primary transfer roller 5M as a primary transfer unit, and a cleaning unit 6M. The image forming unit 10C that forms a cyan image includes a drum-shaped photoreceptor 1C, a charging unit 2C, an exposure unit 3C, a developing unit 4C, a primary transfer roller 5C as a primary transfer unit, and a cleaning unit 6C. The image forming unit 10Bk for forming a black image includes a drum-shaped photoreceptor 1Bk, a charging unit 2Bk, an exposure unit 3Bk, a developing unit 4Bk, a primary transfer roller 5Bk as a primary transfer unit, and a cleaning unit 6Bk. The image forming apparatus of the present invention uses the above-described photoreceptor of the present invention as the photoreceptors 1Y, 1M, 1C, and 1Bk.

  The four sets of image forming units 10Y, 10M, 10C, and 10Bk are centered on the photoreceptors 1Y, 1M, 1C, and 1Bk, and charging units 2Y, 2M, 2C, and 2Bk, and exposure units 3Y, 3M, 3C, and 3Bk. , Rotating developing means 4Y, 4M, 4C and 4Bk, and cleaning means 6Y, 6M, 6C and 6Bk for cleaning the photoreceptors 1Y, 1M, 1C and 1Bk.

  The image forming units 10Y, 10M, 10C, and 10Bk have the same configuration except that the colors of toner images formed on the photoreceptors 1Y, 1M, 1C, and 1Bk are different, and the image forming unit 10Y is taken as an example in detail. explain.

  In the image forming unit 10Y, a charging unit 2Y, an exposure unit 3Y, a developing unit 4Y, and a cleaning unit 6Y are arranged around a photoconductor 1Y that is an image forming body, and a yellow (Y) toner image is placed on the photoconductor 1Y. To form. In the present embodiment, in the image forming unit 10Y, at least the photosensitive member 1Y, the charging unit 2Y, the developing unit 4Y, and the cleaning unit 6Y are provided so as to be integrated.

The charging unit 2Y is a unit that applies a uniform potential to the photoreceptor 1Y. In the present invention, the charging means is preferably a contact or non-contact roller charging type. As for the application method, a method in which an AC bias is superimposed on a DC bias is desirable from the viewpoint of image quality, but there is no problem with only the DC bias.
Because the charging means is a contact or non-contact roller charging system, the amount of ozone generated can be greatly reduced, and the applied voltage can be reduced compared to the corona charging system. In addition, space can be saved.

  The exposure unit 3Y is a unit that performs exposure based on an image signal (yellow) on the photoreceptor 1Y to which a uniform potential is applied by the charging unit 2Y, and forms an electrostatic latent image corresponding to a yellow image. As the exposure means 3Y, a device composed of an LED having light emitting elements arranged in an array in the axial direction of the photoreceptor 1Y and an imaging element, a laser optical system, or the like is used.

  The developing means 4Y includes, for example, a developing sleeve that contains a magnet and rotates while holding the developer, and a voltage applying device that applies a DC and / or AC bias voltage between the photosensitive member and the developing sleeve.

  The fixing unit 24 is, for example, a heat roller fixing configured by a heating roller having a heating source therein and a pressure roller provided in pressure contact with the heating roller so as to form a fixing nip portion. One of the methods is mentioned.

  The cleaning unit 6Y includes a cleaning blade and a brush roller provided on the upstream side of the cleaning blade.

Specifically, as shown in FIG. 5, the cleaning means 6 includes a cleaning blade 66A provided so that the tip abuts against the surface of the photoconductor 1, and the photoconductor 1 provided upstream of the cleaning blade 66A. It is comprised by the brush roller 66C which contacts the surface.
In FIG. 5, reference numeral 2A denotes a charging roller, 2B denotes a cleaning roller, 9 denotes a static eliminating unit, 44A denotes a developing roller, 44B denotes a supply screw, 44C denotes a conveying screw, 44D denotes a regulating blade, and 66J denotes a conveying screw.

  The cleaning blade 66 </ b> A has a function of removing the residual toner attached to the photoconductor 1 and a function of rubbing the surface of the photoconductor 1.

  The cleaning blade 66A is supported by a support member 66B. A rubber elastic body is used as the material of the cleaning blade 66A, and urethane rubber, silicon rubber, fluorine rubber, chloropyrene rubber, butadiene rubber, and the like are known as the material. Among these, urethane rubber is other materials. It is particularly preferable in that it has excellent wear characteristics compared to other rubbers.

  The support member 66B is configured by a plate-like metal member or a plastic member. Examples of the metal member include a stainless steel plate, an aluminum plate, and a vibration control steel plate.

  In the present invention, it is preferable that the tip of the cleaning blade 66 </ b> A that contacts the surface of the photoconductor 1 abuts in a state where a load is applied in a direction opposite to the rotation direction of the photoconductor 1 (counter direction). As shown in FIG. 5, it is preferable that the tip of the cleaning blade 66 </ b> A forms a contact surface when it comes into contact with the photoreceptor 1.

The cleaning unit 6 includes a lubricant application mechanism that applies a lubricant to the surface of the photoreceptor 1.
Specifically, a solid material (not shown) of a lubricant pressed against the brush roller 66C by a load spring (not shown) is provided, and the solid material is abraded by the rotation of the brush roller 66C. Then, a lubricant is applied to the surface of the photoreceptor 1.
As the lubricant, for example, zinc stearate can be used.

  The image forming apparatus of the present invention is configured by integrally combining the above-described photosensitive member, developing unit, cleaning unit and the like as a process cartridge (image forming unit), and this image forming unit is connected to the apparatus main body. It may be configured to be detachable. In addition, a process cartridge (image forming unit) is formed by integrally supporting at least one of a charging unit, an exposure unit, a developing unit, a transfer unit, and a cleaning unit together with a photosensitive member, and is detachably attached to the apparatus main body. The forming unit may be configured to be detachable using guide means such as a rail of the apparatus main body.

  The endless belt-like intermediate transfer body unit 7 includes an endless belt-like intermediate transfer body 70 as a second image carrier having a semiconductive endless belt shape that is wound around a plurality of rollers and is rotatably supported.

  Each color image formed by the image forming units 10Y, 10M, 10C, and 10Bk is sequentially transferred onto a rotating endless belt-shaped intermediate transfer body 70 by primary transfer rollers 5Y, 5M, 5C, and 5Bk as primary transfer means. Thus, a synthesized color image is formed. A transfer material (image support for carrying a fixed final image: for example, plain paper, transparent sheet, etc.) P housed in the paper feed cassette 20 is fed by a paper feed means 21 and includes a plurality of intermediate rollers 22A, After passing through 22B, 22C, 22D and the registration roller 23, it is conveyed to the secondary transfer roller 5b as the secondary transfer means, and is secondarily transferred onto the transfer material P, and the color images are collectively transferred. The transfer material P onto which the color image has been transferred is subjected to fixing processing by the fixing unit 24, is sandwiched between paper discharge rollers 25, and is placed on a paper discharge tray 26 outside the apparatus. Here, a transfer support for a toner image formed on a photosensitive member such as an intermediate transfer member or a transfer material is collectively referred to as a transfer medium.

  On the other hand, after the color image is transferred to the transfer material P by the secondary transfer roller 5b as the secondary transfer means, the residual toner is removed by the cleaning means 6b from the endless belt-shaped intermediate transfer body 70 in which the transfer material P is separated by curvature. The

  During the image forming process, the primary transfer roller 5Bk is always in contact with the photoreceptor 1Bk. The other primary transfer rollers 5Y, 5M, and 5C are in contact with the corresponding photoreceptors 1Y, 1M, and 1C, respectively, only during color image formation.

  The secondary transfer roller 5b contacts the endless belt-shaped intermediate transfer body 70 only when the transfer material P passes through the secondary transfer roller 5b.

  Further, the housing 8 can be pulled out from the apparatus main body A through the support rails 82L and 82R.

  The housing 8 includes image forming units 10Y, 10M, 10C, and 10Bk and an endless belt-shaped intermediate transfer body unit 7.

  The image forming units 10Y, 10M, 10C, and 10Bk are arranged in tandem in the vertical direction. An endless belt-shaped intermediate transfer body unit 7 is disposed on the left side of the photoreceptors 1Y, 1M, 1C, and 1Bk in the drawing. The endless belt-shaped intermediate transfer body unit 7 includes an endless belt-shaped intermediate transfer body 70 that can be rotated by winding rollers 71, 72, 73, 74, primary transfer rollers 5Y, 5M, 5C, 5Bk, and a cleaning unit 6b. Consists of.

  In the image forming apparatus shown in FIG. 4, a color laser printer is shown, but the present invention can be similarly applied to a monochrome laser printer and a copy. The exposure light source may also be a light source other than a laser, such as an LED light source.

  According to the image forming apparatus as described above, by providing the photoreceptor of the present invention, good cleaning properties can be obtained, so that a high-quality image can be formed over a long period of time, and the supply of lubricant Even when unevenness occurs, the occurrence of uneven image density is suppressed.

(Image forming method)
The image forming method of the present invention comprises a charging step for charging the surface of a photoreceptor, an exposure step for forming an electrostatic latent image on the surface of the photoreceptor, and developing the electrostatic latent image with toner to form a toner image. A developing step, a transfer step for transferring the toner image to the transfer material, a fixing step for fixing the toner image transferred to the transfer material, and a cleaning step for removing residual toner on the photoreceptor. Includes a lubricant, and the photoreceptor of the present invention is used as the photoreceptor. The charging step is preferably performed by a contact or non-contact roller charging method.

The image forming method of the present invention can be executed using, for example, the image forming apparatus shown in FIG. In the image forming method of the present invention, the image forming apparatus may be provided with a lubricant application mechanism, or a developer containing a lubricant as a developer may be used. When the developer contains a lubricant, the lubricant is supplied to the surface of the photoreceptor by a developing electric field in the development process.
The lubricant is not particularly limited as long as it has lubricity and cleavage, but for example, zinc stearate can be used. The number average primary particle size of the lubricant is preferably 1 to 20 μm, for example. The lubricant is preferably contained in the developer in a proportion of 0.01 to 0.3% by mass so as not to affect the chargeability of the toner.

  In the above image forming method, by using the photoreceptor of the present invention, good cleaning properties can be obtained, so that a high quality image can be formed over a long period of time, and uneven supply of the lubricant occurs. Even in this case, the occurrence of uneven image density is suppressed.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited only to a following example. In the following, “part” means “part by mass”.

[Photoconductor Production Example 1]
The surface of an aluminum cylinder having a diameter of 60 mm was cut to prepare a conductive support [1] having a fine and rough surface.

(Formation of intermediate layer)
A dispersion having the following composition was diluted twice with the same solvent as described below, and allowed to stand overnight, followed by filtration (filter; using a lymesh 5 μm filter manufactured by Nihon Pall Co., Ltd.) to prepare an intermediate layer forming coating solution [1]. .
Binder resin: Polyamide resin “CM8000” (manufactured by Toray Industries, Inc.) 1 part Metal oxide particles: Titanium oxide “SMT500SAS” (manufactured by Teica) 3 parts Solvent: Methanol 10 parts Batch using a sand mill as a disperser for 10 hours Was distributed.
An intermediate layer [1] having a dry film thickness of 2 μm was formed on the conductive support [1] using the intermediate layer forming coating solution [1] by dip coating.

(Formation of charge generation layer)
Charge generation material: 20 parts of the following pigment (CG-1), binder resin: 10 parts of polyvinyl butyral resin “# 6000-C” (manufactured by Denki Kagaku Kogyo), solvent: 700 parts of t-butyl acetate, solvent: 4-methoxy 300 parts of -4-methyl-2-pentanone was mixed and dispersed for 10 hours using a sand mill to prepare a coating solution [1] for forming a charge generation layer. This charge generation layer forming coating solution [1] was applied onto the intermediate layer [1] by a dip coating method to form a charge generation layer [1] having a dry film thickness of 0.3 μm.

<Synthesis of Pigment (CG-1)>
(1) Synthesis of amorphous titanyl phthalocyanine 1,3-diiminoisoindoline; 29.2 parts are dispersed in 200 parts of o-dichlorobenzene, and titanium tetra-n-butoxide; 20.4 parts are added under a nitrogen atmosphere. For 5 hours at 150-160 ° C. After allowing to cool, the precipitated crystals were filtered, washed with chloroform, washed with 2% aqueous hydrochloric acid, washed with water, washed with methanol, and dried to obtain 26.2 parts (yield 91%) of crude titanyl phthalocyanine.
Next, the crude titanyl phthalocyanine was dissolved by stirring for 1 hour in 250 parts of concentrated sulfuric acid at 5 ° C. or less, and this was poured into 5000 parts of water at 20 ° C. The precipitated crystals were filtered and sufficiently washed with water to obtain 225 parts of a wet paste product.
This wet paste product was frozen in a freezer, thawed again, filtered and dried to obtain 24.8 parts of amorphous titanyl phthalocyanine (yield 86%).

(2) Synthesis of (2R, 3R) -2,3-butanediol adduct titanyl phthalocyanine (CG-1) 10.0 parts of the above amorphous titanyl phthalocyanine and (2R, 3R) -2,3-butanediol 94 parts (0.6 equivalent ratio) (equivalent ratio is equivalent ratio to titanyl phthalocyanine, hereinafter the same) was mixed in 200 parts of orthochlorobenzene (ODB) and stirred at 60 to 70 ° C. for 6.0 hours. After standing overnight, methanol was added to the reaction solution, and the resulting crystals were filtered. The crystals after filtration were washed with methanol (a pigment containing (2R, 3R) -2,3-butanediol adduct titanyl phthalocyanine). CG-1: 10.3 parts were obtained. In the X-ray diffraction spectrum of the pigment (CG-1), there are clear peaks at 8.3 °, 24.7 °, 25.1 °, and 26.5 °. There is a peak in the 576 and 648 in the mass spectra, O-Ti-O both absorption appears Ti = O near 970 cm ^-1, around 630 cm ^-1 in the IR spectrum. In addition, since thermal analysis (TG) has a mass loss of about 7% at 390 to 410 ° C., a 1: 1 adduct and a non-adduct (addition) of titanyl phthalocyanine and (2R, 3R) -2,3-butanediol (Not) presumed to be a mixture of titanyl phthalocyanine.
It was 31.2 m < ² > / g when the BET specific surface area of the obtained pigment (CG-1) was measured with the flow type specific surface area automatic measuring apparatus (Micrometrics flow soap type: Shimadzu Corporation).

(Formation of charge transport layer)
Charge transport material: 225 parts of the following compound A, binder resin: 300 parts of polycarbonate resin “Z300” (manufactured by Mitsubishi Gas Chemical), antioxidant: 6 parts of “Irganox 1010” (manufactured by Ciba Geigy Japan), solvent: THF (tetrahydrofuran) 1600 Part, solvent: 400 parts of toluene and 1 part of silicone oil “KF-50” (manufactured by Shin-Etsu Chemical Co., Ltd.) were mixed and dissolved to prepare a coating solution [1] for forming a charge transport layer.
The charge transport layer forming coating solution [1] was applied onto the charge generation layer [1] using a circular slide hopper coating apparatus to form a charge transport layer [1] having a dry film thickness of 20 μm.

(Formation of surface layer)
(1) Preparation of metal oxide fine particles 100 parts of tin oxide (number average primary particle size: 20 nm), 30 parts of exemplary compound (S-13) as a surface treatment agent, toluene / isopropyl alcohol = 1/1 (mass ratio) A mixed solution of 300 parts of a mixed solvent was placed in a sand mill together with zirconia beads and stirred at about 40 ° C. at a rotational speed of 1500 rpm. Further, the treated mixture was taken out, put into a Henschel mixer and stirred at a rotational speed of 1500 rpm for 15 minutes. By drying at 120 ° C. for 3 hours, the surface treatment of tin oxide with the compound having a radical polymerizable functional group was completed, and surface-treated tin oxide was obtained. This is designated as metal oxide fine particles [1]. The surface of the tin oxide particles was coated with the exemplary compound (S-13) by the surface treatment with the compound having the radical polymerizable functional group.

(2) Formation of surface layer 150 parts of metal oxide fine particles [1], polyfunctional radical polymerizable organic compound: 100 parts of the exemplified compound (M1), charge transporting compound: 20 parts of the exemplified compound (CTM-10) After mixing under light shielding, 400 parts of solvent: 2-butanol and 20 parts of solvent: tetrahydrofuran were mixed and stirred and dispersed for 5 hours using a sand mill as a disperser. Then, polymerization initiator: “Irgacure 819” (BASF Japan Ltd.) 12.5 parts) and organic resin fine particles: “Eposter S” (manufactured by Nippon Shokubai Co., Ltd.) 10 parts were added and mixed and stirred for 1 hour to prepare a surface layer forming coating solution [1]. The surface layer forming coating solution [1] is applied onto the charge transport layer [1] using a circular slide hopper coating device to form a coating film, and irradiated with ultraviolet rays for 1 minute using a metal halide lamp, followed by drying. A surface layer [1] having a film thickness of 2.5 μm was formed to produce a photoreceptor [1].

[Photoconductor Production Examples 2 to 9]
Photoreceptors [2] to [9] were produced in the same manner as in the formation of the surface layer in Production Example 1 of the photoreceptor, except that the type and amount of organic resin fine particles used were changed according to Table 1.

[Photoconductor Production Example 10]
A photoreceptor [10] was produced in the same manner as in the formation of the surface layer in Production Example 1 of the photoreceptor, except that no charge transporting compound was added.

[Photoconductor Production Example 11]
A photoreceptor [11] was produced in the same manner as in the formation of the surface layer in Production Example 1 of the photoreceptor, except that no organic resin fine particles were added.

[Photosensitive member production example 12]
A photoreceptor [12] was produced in the same manner as in the formation of the surface layer in Production Example 1 of the photoreceptor, except that the metal oxide fine particles were not added.

[Examples 1 to 10, Comparative Examples 1 and 2]
The photoreceptors [1] to [12] obtained as described above were evaluated for the following cleaning properties, image density unevenness, and abrasion resistance.

(1) Evaluation of cleaning property The cleaning property was determined visually by using an external drive machine to determine whether or not the toner band developed on the photosensitive member could be wiped off with a blade.
Specifically, a modified image forming unit “bizhubProC6500” (manufactured by Konica Minolta Co., Ltd.) was used and set in an external drive. At that time, the end-of-end image forming unit was used. As shown in FIG. 5, the image forming unit includes a photoconductor (1), a charging unit (2), a developing unit (4), a cleaning unit (cleaning blade) (6), and a housing. The developing means (4) is a two-component developing system, and includes a developing roller (44A) (consisting of a magnet roll / developing sleeve), a regulating blade (44D), a supply / conveying screw (44B, 44C), and a housing. . The external driver can drive the photosensitive member and the developing roller, and can apply a predetermined developing bias to the developing roller.
The evaluation method is as follows.
(1) Set the image forming unit in the external drive.
(2) A high voltage power supply output line is connected to the developing means (developing roller), and the developing bias is adjusted by DC development so that the toner amount on the photosensitive member is 2 g / m ² . At this time, a necessary amount of toner is replenished in a timely manner to prevent a decrease in toner concentration in the developer.
(3) The image forming unit is driven as it is for 5 seconds, then a developing bias is applied for 0.5 seconds, and then rotated for 0.3 seconds and then stopped.
(4) The level of toner remaining on the photosensitive member is evaluated according to the following evaluation criteria.
-Evaluation criteria-
○: No wiping left △: Stripped wiping left ×: Surface wiping generated

(2) Evaluation of unevenness in image density Using an actual machine, 10 A4 charts of half-solid black and half-solid white as shown in FIG. 6 (A) are printed, and then halftone image output shown in FIG. 6 (B) is performed. The image density difference between the solid black history portion and the white solid history portion is evaluated according to the following evaluation criteria. The image density is measured by “TD-904” manufactured by Macbeth.
-Evaluation criteria-
○: Density difference is less than 0.02 Δ: Density difference is 0.02 or more and less than 0.03 ×: Density difference is 0.03 or more

(3) Evaluation of wear resistance After outputting 100 k character charts corresponding to a printing rate of 5% on an actual machine, the amount of wear on the surface layer was measured by a measuring instrument “FISCHERSCOPE (registered trademark) MMS (registered trademark)” manufactured by Fischer. PC "was measured and evaluated. The case where the amount of depletion of the surface layer was less than 0.6 μm was evaluated as ◎, the case where it was 0.6 μm or more and less than 1.2 μm was evaluated as ◯, and the case where it was 1.2 μm or more was evaluated as ×.

1,1Y, 1M, 1C, 1Bk photoconductor 2,2Y, 2M, 2C, 2Bk charging means 2A charging roller 2B cleaning roller 3,3Y, 3M, 3C, 3Bk exposure means 4,4Y, 4M, 4C, 4Bk developing means 5Y, 5M, 5C, 5Bk Primary transfer roller 5b Secondary transfer roller 6, 6Y, 6M, 6C, 6Bk, 6b Cleaning means 7 Intermediate transfer unit 8 Housing 9 Discharge means 10, 10Y, 10M, 10C, 10Bk Image formation Unit 21 Paper feed means 20 Paper feed cassette 22A, 22B, 22C, 22D Intermediate roller 23 Registration roller 24 Fixing means 25 Paper discharge roller 26 Paper discharge tray 44A Development roller 44B Supply screw 44C Transport screw 44D Regulation blade 66A Cleaning blade 66B Support member 66C brush roller 66 Conveying screw 70 Endless belt-like intermediate transfer member 71, 72, 73, 74 Rollers 82L, 82R Support rail P Transfer material 101 Conductive support member 102 Photosensitive layer 103 Intermediate layer 104 Charge generation layer 105 Charge transport layer 106 Surface layer 107a Organic resin Fine particles 107b Metal oxide fine particles 251 Base material 254 Storage tank 255 Pressure pump 260 Application head 261 Application liquid outlet 262 Application liquid distribution slit 263 Application liquid distribution chamber 264 Supply pipe 265 Slide surface 266 Lip part 267 Discharge port L Application liquid F Coating

Claims (10)

In an electrophotographic photosensitive member in which a photosensitive layer is formed on a conductive support and a surface layer is formed on the photosensitive layer,
The surface layer is formed by containing organic resin fine particles and metal oxide fine particles in a cured resin that is a polymerization reaction product of a compound having two or more radical polymerizable functional groups,
The organic resin fine particles are made of a resin containing a structural unit derived from at least one of melamine and benzoguanamine, and have a number average primary particle size of 0.01 to 3.00 μm. .   The electrophotographic photoreceptor according to claim 1, wherein the organic resin fine particles are made of a polycondensate of melamine and formaldehyde.   The electrophotographic photosensitive member according to claim 1, wherein the organic resin fine particles are contained in a ratio of 5 to 40 parts by mass with respect to 100 parts by mass of the cured resin.   The electrophotographic photosensitive member according to any one of claims 1 to 3, wherein the metal oxide fine particles are surface-treated with a surface treatment agent comprising a compound having a radical polymerizable functional group. body.   5. The electrophotographic photosensitive member according to claim 1, wherein the curable resin is an acrylic resin.   6. The electrophotographic photoreceptor according to claim 1, wherein the surface layer contains a charge transporting compound. An electrophotographic photosensitive member; a charging unit that charges the surface of the electrophotographic photosensitive member; an exposing unit that forms an electrostatic latent image on the surface of the electrophotographic photosensitive member; and developing the electrostatic latent image with toner Developing means for forming a toner image by developing with an agent, transfer means for transferring the toner image to a transfer material, fixing means for fixing the toner image transferred to the transfer material, and residual on the electrophotographic photosensitive member Cleaning means for removing toner,
Having a lubricant application mechanism for applying a lubricant to the surface of the electrophotographic photoreceptor,
An image forming apparatus, wherein the electrophotographic photosensitive member is the electrophotographic photosensitive member according to claim 1.   The image forming apparatus according to claim 7, wherein the charging unit is of a contact or non-contact roller charging type. A charging step for charging the surface of the electrophotographic photosensitive member, an exposure step for forming an electrostatic latent image on the surface of the electrophotographic photosensitive member, and a toner image obtained by developing the electrostatic latent image with a developer containing toner. A developing step for forming the toner image, a transferring step for transferring the toner image to a transfer material, a fixing step for fixing the toner image transferred to the transfer material, and a cleaning step for removing residual toner on the electrophotographic photoreceptor. Have
The developer includes a lubricant;
An image forming method using the electrophotographic photosensitive member according to claim 1 as the electrophotographic photosensitive member.   The image forming method according to claim 9, wherein the charging step is performed by a contact or non-contact roller charging method.